Cytokine production in mice with experimental cardiomyopathy treated with anti-L3T4 monoclonal antibody at different stages

AIM: To clarify the mechanism of treating autoimmune cardiomyopathy at different stages with anti-L3T4 monoclonal antibody. METHODS: Mice immunized with human mitochondria ADP/ATP peptides were used as the cardiomyopathy (DCM) group, and the sham-immunized mice were regarded as the controls. Mice receiving early treatment were immunized with the same peptides, followed by the injection of 400 μg of anti-L3T4 on day 0, 1 and 2 post-immunization. Mice in the late treatment group were immunized as of the early treatment group but anti-L3T4 was administered 3 months post-immunization. The cytokine expression was measured with three-color flow cytometry to quantitate the splenic Th1/Th2 cell subsets in the different groups of mice. In addition, serum and myocardial cytokines were measured by enzyme-linked immunosorbent assay and real-time PCR. RESULTS: Th1 and Th2 subsets in the early treatment group were similar to those in control group, but were drastically lower than those in DCM group. Mice in the late treatment group showed an increased level of Th1-related cytokines, while the Th2 level was between the DCM and early treatment group. IFN-γ and IL-6 levels in early treatment group were similar to those in control group. In the early treatment group, IL-4 level was higher than that in control and lower than that in DCM group, whereas IL-2 and TNF-α contents were lower than those in control and DCM group. In the late treatment group, IFN-γ and IL-2 levels were higher than those in DCM group and lower than those in the early treatment group, while IL-6 and IL-4 levels were lower than those in DCM group. CONCLUSION: These results suggest that the cytokine production in cardiomyopathic mice may be repressed by treatment with anti-L3T4 at different stages. Early treatment with anti-L3T4 has better inhibitory function than treatment in late stage of autoimmune cardiomyopathy.